CHICAGO – What has already been a stormy week in the Midwest and Great Lakes takes another punch from Mother Nature on Friday.
Severe thunderstorms threaten to blast the region from the Dakotas through Chicago and into the Great Lakes with strong winds, heavy rains and large hail.
Thunderstorms were already pushing through the area Friday morning, even triggering a ground stop at Chicago’s O’Hare and Midway airports, but stronger storms were forecast later in the day.
Extremely warm and muggy air that has been a staple of the past several days in the Midwest, placing millions under Heat Advisories and Excessive Heat Warnings, will shift north out of Nebraska, Iowa and Illinois Friday morning.
The surge of heat will eventually mix with a stalled front that has been draped over Minnesota and Wisconsin, providing fuel for an unstable atmosphere that will set the stage for severe thunderstorms Friday afternoon and evening.
NOAA’s Storm Prediction Center has placed over 13 million in an area stretching from Chicago west to around Sioux Falls, Iowa in a Level 3 out of 5 on their severe weather risk scale. A level 2 risk extends farther east into Great Lakes, covering 27 million more from Milwaukee out to Indianapolis, Detroit and Cleveland.
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Storms look to first fire in the mid-afternoon in eastern South Dakota and northern Iowa into southern Wisconsin and at first, present more of a large hail threat amid individual storms.
But as the evening progresses, thunderstorms will likely congeal into squall lines that present more of a damaging wind threat with gusts of at least 60 mph as they sweep into southern Wisconsin and northern Illinois, including the Milwaukee and Chicagoland area. Forecast charts peg the storms rolling into the Windy City around 8-10 p.m.
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More thunderstorms will develop ahead of the line in Indiana and Ohio Friday evening, also carrying a large hail and damaging wind threat.
The good news is the tornado risk is very low.
In addition to the wind and hail threat, heavy rains will present a risk of flash flooding over the southern Great Lakes area, as already-soaked soils won’t allow for much additional rain before flash flooding begins.
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As much as 1-3 inches of rain could fall in these thunderstorms, inundating places like Milwaukee, Chicago, and Detroit with street flooding, according to the FOX Forecast Center.
A much quieter Saturday is expected in the Great Lakes as the severe storm threat shifts east to the mid-Atlantic and Northeast.
There, a risk of severe thunderstorms will stretch from Boston through New York and down the I-95 corridor into Philadelphia and Washington.
Severe Thunderstorm Watches were issued for millions across the Upper Midwest and Great Lakes on Thursday as storms moved across the region.
During the height of the severe weather, more than 200,000 outages were reported by data from PowerOutage.us.
The SPC received reports of half dollar-sized hail in Minnesota and a wind gust to 70 mph in Wisconsin.
Hail the size of quaters was reported north of Minneapolis, as the downtown region missed out on the strongest storms.